MacConkey agar differentiates lactose fermenters from non-fermenters among Gram-negative enteric bacteria. Which organism is a lactose fermenter?
Anonymous Quiz
25%
A) Pseudomonas aeruginosa
67%
B) Escherichia coli
4%
C) Proteus mirabilis
4%
D) Salmonella typhi
In an ELISA, which component serves as the blocking step to prevent non-specific binding?
Anonymous Quiz
11%
A) Primary antibody
39%
B) Enzyme conjugate
42%
C) Blocking buffer
8%
D) Substrate solution
Which immunoglobulin is the first antibody produced in a primary immune response and is a pentamer?
Anonymous Quiz
9%
A) IgG
23%
B) IgA
64%
C) IgM
4%
D) IgE
How is a 4-fold rise in antibody titer between acute and convalescent sera interpreted?
Anonymous Quiz
5%
A) Chronic infection
79%
B) Acute infection or recent exposure
16%
C) Vaccination response only
0%
D) No clinical significance
Which sequence correctly describes routine tissue processing before paraffin embedding?
Anonymous Quiz
13%
A) Dehydration, clearing, fixation, infiltration
77%
B) Fixation, dehydration, clearing, infiltration
6%
C) Infiltration, fixation, dehydration, clearing
4%
D) Clearing, fixation, dehydration, infiltration
Which statement about hematoxylin and eosin (H&E) staining is true?
Anonymous Quiz
12%
A) Hematoxylin is acidic and stains light structures
21%
B) Eosin stains nucleic acids blue
65%
C) Hematoxylin stains basophilic structures blue/purple
1%
D) Eosin stains DNA strongly
Which dipstick result combination suggests proteinuria and glycosuria?
Anonymous Quiz
60%
A) Positive protein, positive glucose
24%
B) Positive protein, negative glucose
11%
C) Negative protein, negative glucose
6%
D) Positive glucose only
Which statement is true about urine specific gravity (USG)?
Anonymous Quiz
73%
A) It measures solute concentration and is influenced by hydration
15%
B) It is identical to osmolality
5%
C) It is not affected by hydration
7%
D) It measures pH
Numerous squamous epithelial cells in a urine sediment sample most likely indicate:
Anonymous Quiz
6%
A) Concentrated urine
82%
B) Contamination from the external genitalia/urethra
8%
C) Pyelonephritis
4%
D) Glomerulonephritis
Which transfusion reaction is most likely with ABO-incompatible plasma transfusion?
Anonymous Quiz
47%
A) Febrile non-hemolytic
35%
B) Acute hemolytic
9%
C) Delayed hemolytic
9%
D) Allergic
RhD immune globulin is indicated in which situation?
Anonymous Quiz
21%
A) Rh-positive mother with an Rh-positive fetus
71%
B) Rh-negative mother carrying an Rh-positive fetus
9%
C) All pregnant women regardless of Rh status
0%
D) Only after a transfusion reaction
Which Westgard rule signals a potential shift when two consecutive control results exceed the same limit (±2 SD)?
Anonymous Quiz
7%
A) 1s rule
67%
B) 2s rule
23%
C) 22s rule
3%
D) R4s rule
Which statement distinguishes calibration from verification in instrument quality control?
Anonymous Quiz
81%
A) Calibration adjusts instrument performance; verification confirmsongoing performance
15%
B) Verification replaces calibration when bias is detected
1%
C) Calibration uses patient samples only
3%
D) Verification increases the calibration frequency unnecessarily
Which PPE is most appropriate when handling volatile solvents in the laboratory?
Anonymous Quiz
3%
A) Safety glasses only
96%
B) Lab coat, gloves, and eye protection; chemical splash goggles; possible respirator
0%
C) None
1%
D) Only gloves
A 30-year-old woman with iron deficiency anemia has a reticulocyte count of 0.8% (normal 0.5-2.5%). This indicates:
Anonymous Quiz
29%
A) Appropriate marrow response to anemia
40%
B) Inadequate marrow response to anemia
26%
C) Marked reticulocytosis due to hemolysis
5%
D) Recent blood loss with transient reticulocytosis
In a colorimetric assay, what is the primary purpose of generating a standard curve?
Anonymous Quiz
9%
A) To determine the sample's color intensity
69%
B) To relate absorbance to known concentrations for quantification
22%
C) To calibrate the spectrophotometer wavelength accuracy
0%
D) To adjust pH of reagents
Which order correctly lists the steps of a conventional Gram stain?
Anonymous Quiz
80%
A) Crystal violet -> iodine -> decolorization with ethanol -> safranin
16%
B) Crystal violet -> safranin -> iodine -> decolorization
3%
C) Iodine -> crystal violet -> decolorization -> safranin
2%
D) Safranin -> crystal violet -> iodine -> decolorization
In an ELISA, which control is essential to validate that a negative result is truly negative?
Anonymous Quiz
20%
A) Positive control
63%
B) Negative control
13%
C) Substrate control
5%
D) Enzyme control
What does hematoxylin primarily stain in tissue sections?
Anonymous Quiz
15%
A) Cytoplasmic proteins
79%
B) Nucleic acids (basophilic nuclei)
5%
C) Collagen fibers
2%
D) Lipids
Which of the following is most likely associated with a positive nitrite dipstick result?
Anonymous Quiz
7%
A) Leukocyte esterase
15%
B) Urobilinogen
74%
C) Bacteriuria due to Gram-negative organisms
5%
D) Proteinuria